Electronic components are used in ever increasing numbers of consumer and commercial electronic products. Examples of some of these consumer and commercial products are televisions, personal computers, internet servers, cell phones, pagers, palm-type organizers, portable radios, car stereos, or remote controls. As the demand for these consumer and commercial electronics increases, there is also a demand for those same products to become smaller, more functional, and more portable for consumers and businesses.
As a result of the size decrease in these products, the components that comprise the products must also become smaller. Examples of some of those components that need to be reduced in size or scaled down are printed circuit or wiring boards, resistors, wiring, keyboards, touch pads, and chip packaging.
Components, therefore, are being broken down and investigated to determine if there are better building materials and methods that will allow them to be scaled down to accommodate the demands for smaller electronic components. In layered components, one goal appears to be decreasing the number of the layers at the same time increasing the layers routing density. This task can be difficult, however, given that several of the layers and components of the layers should generally be present in order to operate the device.
Thus, there is a continuing need to: a) design and produce layered materials that meet customer specifications while minimizing the size of the device and number of layers; and b) develop reliable methods of producing desired layered materials and components comprising those layered materials.
In accordance with the invention there is provided an interface material that comprises a resin mixture and at least one solder material. The resin material may comprise any suitable resin material, but it is preferred that the resin material be silicone-based comprising one or more compounds such as vinyl silicone, vinyl Q resin, hydride functional siloxane and platinum-vinylsiloxane. The solder material may comprise any suitable solder material, such as indium, silver, copper, aluminum, tin, bismuth, gallium and alloys thereof, silver coated copper, and silver coated aluminum, but it is preferred that the solder material comprise indium or indium-based compounds.
The interface material, or polymer solder, has the capability of enhancing heat dissipation in high power semiconductor devices and maintains stable thermal performance. It is not subject to interfacial delamination or phase separation during thermal-mechanical stresses or fluctuating power cycling of the electronic devices in which it is used.
The interface material may be formulated by mixing the components together to produce a paste which may be applied by dispensing methods to any particular surface and cured at room temperature or elevated temperature. It can be also formulated as a highly compliant, cured, tacky elastomeric film or sheet for other interface applications where it can be preapplied, for example on heat sinks, or in any other interface situations.
It may be also additionally useful to incorporate antioxidants to reduce oxidation of the polymer-based resins, wetability enhancing agents to promote wetting of surfaces, curing accelerators, such as those accelerators that would allow curing at room temperature, viscosity reducing agents to enhance dispersability and crosslinking aids. It is also sometimes desirable to include substantially spherical particles of filler to limit the compressibility of the interface material in interface applications, i.e. to limit or control the thickness of the material and of the layer.
It has been also found that thermal conductivity of solder systems, such as a combination of filler and the combined resin mixture discussed above, can be especially improved by incorporating carbon micro fibers, with other fillers, into the system.